Teledyne ACCQPrep HP125 Installation And Operation Manual page 56

ACCQPrep HP125
Section 4 Operation
Default Injection Sequence
4-10
injection minimizes the risk of sample crash by placing a small
amount of a user selected solvent on each end of the sample fluid.
All sample injection steps are listed below for reference.
1. During column equilibrium, the sample loop is first placed
into the run position. This position passes the column
equilibration fluid through the loop to wash out any left-
over fluid from a previous separation and fills the loop with
the initial gradient conditions from the current separation.
This prevents any strong solvent remaining in the loop
from affecting the current separation.
2. The sample probe is placed in the wash station.
3. About 1.5 mL of the solvent is pulled from the wash station
through the probe to remove air from the probe line.
4. The sample probe is lifted from the wash station and is
moved up and down slightly. When the sample probe is
dipped in the sample or solvent, some liquid sticks to the
outside of the probe when it is raised. Therefore, the probe
is moved up and down over the fluid source to shake off
any excess liquid and to prevent the contamination of other
samples or collection tubes.
5. A small amount of air (0.05 mL) is drawn into the sample
probe to minimize the mixing of the wash solvent and the
soon to be loaded sample. This also minimizes the potential
of the sample coming out of solution.
6. The sample probe is moved to the sample container.
7. A portion of the programmed injection amount is aspirated
into the sample probe displacing most of the wash solvent
in the sample probe. This compensates for the volume of
the sample probe. Since the loop is still in the separation
position, the wash solvent is sent to waste.
8. The loop is switched to the load position.
9. The remaining portion of the programmed injection volume
is aspirated into the sample probe and loop. Once the pro-
grammed amount of sample is aspirated into the probe, the
probe is lifted out of the sample vial.
10. The probe is moved up and down over the sample tube to
shake off any excess liquid to prevent the contamination of
other samples or collection tubes.
11. The probe is dipped into the wash station to rinse the exte-
rior of the probe to prevent sample residue from drying on
the exterior of the probe.
12. Air is drawn into the sample probe to draw the remaining
sample into the loop without leaving any sample in the
probe.
13. The sample is now loaded and the separation will begin.
14. The next injection of the sample is accomplished by repeat-
ing the above process.
After the completion of the final injection of a sample, the system
washes the probe with the following sequence: